1. Field of the Invention
The present invention relates to an organic electroluminescence device and a manufacturing method thereof, and more particularly, to an organic electroluminescence device which can be applied to a front emission type, a rear emission type or both, and has an improved lifetime by enhanced moisture and oxygen absorbing properties, and a manufacturing method thereof.
2. Description of the Related Art
Since an organic electroluminescence device tends to deteriorate due to infiltration of moisture, there arises a need for an encapsulation member for preventing moisture from infiltrating into the device.
Conventionally, there have been employed several encapsulating methods, including forming a cap-shaped metal can or glass which has a recess so that a powdered absorbent for absorbing moisture is accommodated therein, and forming a film-type double-sided tape for adhesion.
Several drawbacks with use of the conventional absorbent are that the process is complicated, the material and processing costs may increase, the overall thickness of a substrate may increase, and a non-transparent encapsulating substrate disables front emission to be achieved. Also, since etched glass used as the encapsulation member is so brittle that it is easily damaged due to external impacts. The film-type encapsulation member is limited in its capability of preventing moisture infiltration, and tears easily during fabrication or use. That is, the film-type encapsulation member is poor in durability and reliability, so that it cannot be suitably employed for mass production.
Japanese Patent Laid-open Publication No. Hei 9-148066 discloses an organic electroluminescence device comprising a laminate structure in which organic light-emitting material layers formed of organic compounds are disposed between a pair of opposed electrodes, a sealing vessel for preventing the laminate structure from being exposed to external air, and drying means, such as alkali metal oxide or alkali metal oxide, provided inside the sealing vessel. However, the organic electroluminescence device becomes bulky due to the shape of the sealing vessel. Also, even if the device is maintained at a solid state due to moisture absorption by the drying means, it cannot be employed for a front emission display due to opaqueness. Further, as mentioned above, this technique involves a complicated process, resulting in an increase in the material and processing costs.